A flyer frame of the aforedescribed type is described in German Patent Document DE 39 36 518 A1, having a carriage chain which is disposed substantially at the same height as the flyer rail and is located rearwardly thereof. For the replacement of fully wound roving bobbins with empty bobbin tubes, the bobbin rail must be displaced from its working position below the flyer rail to a region behind the latter to cooperate with the carriage chain to which the fully wound bobbins are transferred and from which the empty bobbin tubes are received by appropriate vertical movement.
Since the shifting of the bobbin rail requires a massive operation, because the spindle rail carrying the bobbins also contain the spindle drive mechanism, the mass which has to be shifted is considerable and the apparatus must be highly complex and is of high construction cost. The special requirements of the machine are considerable because space must be provided to allow for shifting of the spindle rail and the bracing of the machine must be increased to carry the load of this spindle rail and the full bobbins rearwardly of the normal location. The flyer rail may then project away from the plane of the center of the machine almost twice as far as is customary and is desirable, thereby exposing the flyer rail and the machine to excessive vibration and stress.
Another arrangement utilizing a guide for a carriage chain adapted to receive the fully wound bobbin and to bring the empty tubes into position for placing upon the spindle is described in EP 0 031 844. This device can serve for the automatic doffing of the full bobbin and application of the empty bobbin tubes in a flyer frame by laterally swinging the flyers to provide a space which from above will afford access to the lowering mechanism having the suspended holders for the empty bobbin tubes and adapted to receive the fully wound bobbin.
This mechanism, again, is costly and frequently is unreliable.
Reference may also be made to German Patent Document DE 27 51 264 which discloses another device to facilitate the doffing of full bobbins from a spindle rail.
In this case, the flyers are provided at the undersides of their heads or yokes with spring clips which can engage in grooves at the upper ends of the roving tubes or sleeves. The tubes or sleeves can be engaged in these clips which serve to draw the full bobbins from the respective spindles when the spindle rail, after engagement of the fully wound tubes, is lowered. The fully wound bobbins must, however, be removed by hand in this system. The system also does not provide for any automatic means for placing the empty tubes on the spindle. Another drawback of this system is that special bobbin tubes are required because of the need for the aforementioned groove at the upper end.
In EP 0 023 193, still another system is described which provides on the underside of the flyer rail of a flyer frame grippers which are swingable into space between arms of the flyers and can engage the upper ends of the fully wound bobbins. These grippers then swing the fully wound bobbin out of the flyers as part of the doffing operation. Hereto, the bobbins must be removed by hand and further manipulated.